The present invention relates to a device for detecting loading of film cartridge built in the photographic camera or other apparatus using a film cartridge, which is for detecting whether a film cartridge is loaded in a loading chamber of the camera or other apparatus.
A variety of cameras using IX 240 type (APS format) film cartridge are on the market. The IX 240 type film cartridge is capable of unwind and thrust out of the cartridge a photographic film strip wound around a spool fixed inside the cartridge by rotating the spool and includes a visual exposure indicator fixed to the spool indicating the film status of use whether the photographic film in the film cartridge is unexposed, partially exposed, fully exposed or developed. The status can be also distinguished by reading a bar code type data recorded in the cartridge by a film status distinguishing mechanism installed in the camera. Upon closing a lid for a cartridge loading chamber after the film cartridge is loaded therein, a spool driving mechanism starts to rotate the spool of the cartridge in the film winding direction. The status is inspected during the spool rotation in the winding direction and the rotational direction is changed only when the status is determined unexposed or partially exposed so that the film can be advanced in film unwinding direction.
It is necessary to confirm whether the film cartridge is loaded in the chamber and the lid is closed before starting the film status distinguishing mechanism. Detecting switches for detecting the film cartridge in the chamber and also detecting switches for detecting a closure of the loading lid have been used for the purpose.
Japanese Laid-open Patent 22059/97 (tokkai-hei 09-22059) and 258325/97 (tokkai-hei 09-258325) show the film cartridge detecting switch mounted on the inner wall of the cartridge loading chamber where the detecting switch is projected from the inner wall so that the switch can be turned on when the outer wall of the film cartridge pushes the switch while the film cartridge being loaded into the chamber. The switch must be disposed at a position where the switch can be pushed only when the film cartridge is completely loaded in a predetermined position.
It may, however, cause disadvantages to install the switch on the inner wall of the film loading chamber, such as complicated process to assemble and to fix when it is needed, which lead to raising manufacturing and repairing costs. Furthermore it will require another space for the installation in addition to spaces for other mechanisms disposed around the loading chamber such as the film status distinguishing mechanism and an opening/closing mechanism for film egress/ingress door unique to the IX 240 type film cartridge, which usually leads to less compactness of the camera.
An object of the invention is to provide a device for detecting loading of film cartridge which is easy to assemble and repair, and not located just around a film loading chamber unlike in conventional cameras. To accomplish the object, following devices are invented.
A device for detecting loading of a film cartridge in a cartridge loading chamber includes a projection member attached to a lid member to cover the cartridge loading chamber and an electric switch incorporated in the lid member. The projection member moves from a first position to a second position when the film cartridge is loaded. The electric switch is changed over to generate a signal for indicating detection of the film cartridge when the projection member moves to the second position.
In the embodiment, the device is incorporated in a camera body. The projection member is spring-biased toward the first position to protrude inside of the cartridge loading chamber, and is engaged with an engaging hole of the spool of the film cartridge to be pushed down to the second position by the spool when the lid member is closed.
The lid member includes an upper cover and a lower cover to which the upper cover is secured, and an inside space is formed therebetween. When the lid member is closed, the upper portion of projection member extends beyond the upper cover by a bias of a spring placed on the inner surface of the lower cover toward inside of the cartridge loading chamber, and the lower portion remains in the inside space. The electric switch is disposed beneath the projection member, normally closed and is open only when the projection member is moved to the second position.
At least a portion of the projection member which is to engage the engaging hole of the cartridge is rotatable so as to be rotated by the spool of the film cartridge.